Carbon dioxide leaking into the walls of a Pooler McDonald’s caused an 80-year-old woman to die last week, investigators have found.

It’s the third time in six years carbon dioxide sickened people at a U.S. McDonald’s.

Pooler death

Pooler police chief Mark Revenew said Anne Felton of Ponte Vedra, Fla., died of asphyxiation after carbon dioxide, used to make the restaurant’s sodas fizzy, leaked into the women’s bathroom of the McDonald’s on Sept. 7.

Revenew said a line used to funnel excess carbon dioxide out of the restaurant got disconnected. The gas, which is kept in tanks in a back room of the McDonald’s, was flowing into the wall next to the women’s bathroom instead of going outside.

Pooler Fire Chief Wade Simmons said the gas runs from the back room into the wall next to the women’s bathroom, then goes up and over the bathroom, running in the ceiling for about 25 feet before reaching the drink machines.

Revenew said that, “given the construction of the restroom, there was very little room for this stuff to dissipate.”

Investigators don’t know yet how the line disconnected, Revenew said, but video surveillance shows that shortly before Felton and Carol Barry — a 56-year-old Jacksonville, Fla., resident — were found unconscious in the bathroom, the restaurant’s carbon dioxide tanks were being refilled.

Revenew and Pooler Fire Chief Wade Simmons said the lines have been repaired. Asked if he would feel safe going to the restaurant now, Revenew said, “I wouldn’t hesitate at all.”

Nine sickened

Nine people — including three firefighters, a McDonald’s employee and a Savannah family of three who tried to help Felton and Barry — were taken to the hospital with dizziness and trouble breathing. Felton died the next day. The other eight people have since been released from Memorial University Medical Center.

John and Monique Palmaccio, franchisees of the McDonald’s, located off U.S. 80 near Interstate 95, released the following statement Wednesday: “... We are committed to running a safe, welcoming restaurant. We worked closely with the authorities to determine the cause of this incident and we’ve taken action to correct the situation. Authorities have conducted a thorough investigation and determined that the restaurant is safe. We are now open for customers ...”

Firefighters were called to the McDonald’s about noon Sept. 7. The restaurant reopened late that afternoon and shut down again about 10 p.m. Tuesday. Pooler authorities said they were testing the lines by filling them with carbon dioxide, and the restaurant’s owners decided to shut down for the safety of employees and patrons.

Cases reported in Phoenix, Florida

According to a material safety data sheet on the gas, carbon dioxide in high concentrations can quickly crowd out the oxygen in the air, leading to dizziness, unconsciousness and, sometimes, death.

Simmons said a Phoenix Fire Department captain contacted him Friday about a carbon dioxide incident that happened at a McDonald’s in that city May 31. That’s when Simmons and Revenew started looking into a possible Pooler leak.

“I’d like to thank the Phoenix Fire Department for putting us on the right track,” Simmons said.

A pregnant, 24-year-old McDonald’s employee passed out in the stairwell to the basement of a Phoenix McDonald’s after being exposed to carbon dioxide, according to the department’s report on the incident.

Two firefighters who responded to the scene also got sick. A broken line on the carbon dioxide tank was the cause, according to the report. The manager of the restaurant said the tank had been refilled a couple hours before the woman passed out.

Carbon dioxide caused two people to die in a Sandford, Fla., McDonald’s in 2005, according to Sandford Fire Department Deputy Chief Craig Radzak.

Radzak said an 18-year-old McDonald’s employee was trying to help a driver for the company that refills the tanks when he died of asphyxiation. The 50-year-old driver died when he tried to help the teen.

McDonald’s open

Simmons and Revenew went to the Pooler McDonald’s Friday night to investigate possible leaking carbon dioxide but didn’t find elevated levels of the gas in the air, so they allowed the restaurant to stay open.

On Saturday, portable bathrooms were set up outside the restaurant. Pooler authorities said the owners rented the bathrooms as a convenience to customers during testing. They still were being used Wednesday.

Simmons praised the Palmaccios for their help with the investigation, which is ongoing.

The U.S. Occupational Safety and Health Administration also is conducting an investigation into the leak. OSHA Area Director Robert Vazzi said he couldn’t comment on the status of that investigation Wednesday other than to say it’s ongoing.